Graphic matter printed on passports and like documents in bound form, for instance but not necessarily in booklet form, generally includes identifying photographs, particularly color photographs, accompanied by identifying data. For this purpose, the laser printing process and laser printing machines are widely used.
Basically, the laser printing process comprises, as a first step, defining the subject matter to be printed in the form of an array of signals that can be used to control the printing machine. A common way of doing this consists in scanning the subject matter to be printed and registering the results of the scanning in a processor's memory, in the form of an array of digital signals. Said signals control the emission of laser rays from a laser source. The laser beams impinge on a cylinder in a pattern controlled by the said signals and electrostatically charge the surface of said metal cylinder at selectively predetermined spots. The selectively electrostatically charged cylinder passes in the vicinity of a reservoir of coloring matter in powder form. The coloring matter particles are attracted to the aforesaid selectively charged spots of said cylinder and form thereon the desired pattern. A print substrate is then passed into contact with the metal cylinder and the pattern formed by the color particles is deposited thereon. This operation is repeated for each color if a multicolor print is desired, usually four times to provide the basic colors magenta, cyan and yellow plus black (black will hereinafter be considered to be a color), to produce a complete colored image. At this stage a colored image has been formed on the print substrate. In order to stabilize the image, the print substrate is passed between heated rollers, which fix or set the print so that it is permanent and stable.
This process is quite effective for a number of applications, but it encounters difficulties, hitherto unsolved, when it is necessary to print on a substrate that is not in the form of a free sheet, but is in bound e.g. in the form a booklet, typically a passport or similar bound document. It would be highly desirable to print on a passport or like document, after it has already been bound in booklet form, the passport holder's photograph, signature, and/or other printed information. However, this is not possible with conventional color laser printing techniques. Other difficulties would arise, should the print substrate have a surface which is not absorbent with respect to the colors: the coloring matter is then partly if not totally transferred from the print substrate to the heat-setting rollers.
Copending Israeli patent application No. 111426, of the present applicant, describes and claims a method for printing on substrates in booklet form, which comprises the following steps:
1--providing a set of instructions, which reverses the original subject matter to be printed to define a reversed subject matter file; PA1 2--providing a temporary substrate, the surface of which is substantially non-absorbent and non-adhesive for the coloring matters to be used for the printing; PA1 3--depositing on said temporary substrate coloring matters, whereby to form thereon said reversed subject matter, by the appropriate steps of the conventional laser printing method; PA1 4--provisionally setting said reversed subject matter by radiant heat; PA1 5--juxtaposing said temporary substrate face-to-face with the final printing substrate; PA1 6--transferring the reversed subject matter from said temporary to said final substrate, whereby said reversed subject matter is reversed and reproduces said original subject matter on said final substrate; and PA1 7--setting said reproduced original subject matter on said final substrate by the application of pressure and optionally heat. PA1 1--providing a set of signals, particularly digital signals, such as a computer file, a frame grabber, a memory buffer or the like, defining the subject matter to be printed (which will be synonimously called hereinafter "the picture" or "the image" or "the original picture or image" or "image file"); PA1 2--providing a temporary or intermediate substrate, the surface of which is substantially non-absorbent and non-adhesive for the coloring matters to be used for the printing or at least is considerably less adhesive and/or absorbent for said coloring matters than the transparent substrate, mentioned hereinafter; PA1 3--depositing on said temporary substrate coloring matters, whereby to produce thereon said original image, by the appropriate steps of the conventional laser printing method; PA1 4--provisionally setting said image without the application of pressure, preferably by radiant heat or dielectric or microwave heating; PA1 5--juxtaposing said temporary substrate with its face carrying said image in contact with the rear face of a transparent printing substrate; PA1 6--transferring said image from said temporary substrate to said transparent substrate rear face, whereby the said image is applied to said transparent substrate rear face and the image is visible, in normal form, through said transparent substrate from the front face thereof and reversed from the rear face; PA1 7--juxtaposing said transparent substrate to the final substrate that is intended to carry the image, with the rear face of said transparent substrate in contact with the front face of said final substrate; and PA1 8--hot or cold laminating said transparent substrate in contact with the front face of said final substrate, permanently to bond them, while said image becomes enclosed in the laminate and visible through said transparent substrate as if printed on said final substrate.
Said process, however, is difficult to carry out and does not provide the desired printing quality, whenever the final substrate does not have a surface that is fully suitable for receiving the reproduced original subject matter and permitting it to be set thereon. This occurs relatively often when said substrate is part of a booklet, particularly a passport, and more particularly when the print is to be effected on the inside of a booklet or passport cover. The cover must have a certain stiffness and is made of a material which possesses it, and, even it is covered by a sheet of paper adhesively connected thereto, its surface irregularities render it unsuitable as substrate for the aforesaid or other known printing methods. On the other hand, printing on the inside of the cover may be preferable or even necessary when the inner sheets are too light or otherwise unsuitable for printing pictures thereon.
It is a purpose of this invention to overcome the aforesaid difficulties and to make it possible satisfactorily to print subject matter, including multicolor subject matter such as data and photographs, on substrates that are part of booklets, particularly of passports and the like.
It is another purpose of this invention to provide a method for printing subject matter, including identifying data and photographs and the like, on the inside of the covers or on any other page of bound substrates, such as passports and the like.
It is a further purpose of this invention to provide an apparatus for achieving the aforesaid results, which apparatus is simple and not expensive to make nor difficult to use.
Other purposes and advantages of this invention will appear as the description proceeds.